This is not recommended, since if the ruby dependency is broken, others will likely be later on, too. Repair this by adding the folder to the $PATH variable like described before, else gem, rake, bundle, passenger-install-apache2-module will not work either... you would have to create symlinks for them later on, too.Symlinks are created like this

Requires C++ compiler to complete. Note: in some CentOS-like linux distros (RHEL, Amazon Linux) the C++ compiler does not come as part of the GCC compiler package. If that's the case, it can be installed with the following command:

yum install gcc-c++

gem install passenger
passenger-install-apache2-module

The install process is interactive and you wil be told what to do. How to install missing dependencies is described exactly. JUST READ!

The other entries are not important, since we will use only the production environment. But if you would need the development or test environment, don't forget the create additional databases. Don't use the same database for production and testing or development environment!

Rails has the concept of environments to represent the stages of an application’s lifecycle: test, development, and production by default. Specify your choice with the RAILS_ENV environment variable. Production has less verbose logging and is a bit faster, testing and development environment are not needed anyway for your Redmine.